The electrostatic painting is a painting method which efficiently applies paint to a vehicle body with an electrostatic attractive force produced by setting the vehicle body at zero voltage and setting the paint at negative voltage. Also, it has been known to mount a painting gun on a robot (see, for example, FIGS. 1 and 2 of Japanese PCT-Based Patent Application Laid-Open Publication No. JP-A 2005-521544 (hereinafter referred to as “Patent Literature 1”).
FIG. 13 is a diagram explanatory of a basic construction of an electrostatic paint apparatus disclosed in Patent Literature 1. A robot 103 is disposed laterally of a conveyor 102 conveying a vehicle body 101, and a painting gun 105 is mounted on an arm 104 of the robot 103. A paint supply section 107 is provided on a building 106 so that a predetermined amount of paint is supplied from the paint supply section 107 to the painting gun 105.
After the paint is supplied to the painting gun 105, the robot 103 turns the arm 104 and ejects or sprays the paint onto the vehicle body 101 by means of the painting gun 105, as shown in FIG. 14. Namely, predetermined electrostatic painting is performed on the vehicle body 101 with the painting gun 105 separated and electrically insulated from the paint supply section 107.
If painting of a multiplicity of different colors is to be performed by use of the single painting gun 105, so-called color change is executed. Cleaning liquid is supplied from the paint supply section 107 to the painting gun 105 to clean the painting gun 105. Next, paint of a desired new color is supplied from the paint supply section 107 to the painting gun 105. Because the paint supply section 107 and the painting gun 105 can be separated from each other, a cleaning range can be selectively limited to the painting gun 105, so that the cleaning liquid can be saved and the cleaning of the painting gun 105 can be done in a short time.
As paint is ejected or sprayed from the painting gun 105 in the illustrated example of FIG. 14, a portion of the sprayed paint may drift around the painting gun 105 as uncoated paint and undesirably adhere to a connection section 108 although most of the sprayed paint runs toward the vehicle body 101. If the sprayed paint adheres to the surface of the connection section 108, the connection section 108 cannot appropriately connect to the paint supply section 107. Thus, there arises a need to clean the connection section 108 at times, so efficiency of the painting operation would decrease because the painting operation is halted temporarily during the cleaning of the connection section 108.
Further, it is necessary to make it difficult for the connection section 108 to be soiled or smeared with the uncoated paint. If the connection section 108 can be made difficult to be smeared, frequency of the cleaning operation can be lowered, and thus, decrease in the efficiency of the painting operation can be minimized.